I don't recall that ever being addressed. And I never really paid it much attention to it before, but as I again glimpse at my copy of UFG, my mind is telling me "what if that was intended to be Mihoshi?". Now that would have made one interesting tie-in to Tenchi.... Thou part of me thinks is could be Dee.

And that thing behind her, I don't know who or what that it is. The outline does not match any of the 3 goddesses, nor does it appear to match any of the robots. So there's another unknown. From what I can see, it appears Dual had some easter eggs thrown into the artwork.

I can see how the way the girl's position appears to look like Mihoshi's in the third OVA, but it is mostly like just D. The silhouette, however, i do wonder who that is, it Does appear like Zinv but slightly altered